Showing papers on "Vermiculite published in 1977"
TL;DR: In this paper, a study was made on the adsorption of phenolic acids, which are known to be plant growth inhibitors, by kaolinite, illite, vermiculite, noncrystalline hydroxy-Al and -Fe compounds, and four Taiwan soils.
Abstract: A study was made on the adsorption of phenolic acids, which are known to be plant growth inhibitors, by kaolinite, illite, vermiculite, noncrystalline hydroxy-Al and -Fe compounds, and four Taiwan soils. The adsorption sequence of phenolic acids by kaolinite, illite, and vermiculite followed
155 citations
TL;DR: In this paper, the most common organic acids present under natural conditions were used on two trioctahedral micas (phlogopite and biotite), and their chemical and mineralogical weathering effects were determined.
Abstract: AB S T RA C T: Aluminous hydroxy 2/I clay minerals ('intergrades') can form in two ways: A1 can either come externally from the solution, or internally from the mineral itself (octahedral or tetrahedral layers). This study is more concerned with the latter which seems the main source in acid soils. The most common organic acids present under natural conditions were used on two trioctahedral micas (phlogopite and biotite), and their chemical and mineralogical weathering effects were determined. Different kinds of mineralogical evolution are possible: mineral destruction by a few very complexing acids, possibly with intermediate stages (interstratified minerals); formation of 'transformation' smectite by acids derived from sugars; Al-hydroxy vermiculite formation (the 14 A diffraction peak of which is stable under K saturation and vacuum). This evolution is the most frequent and is produced by the most numerous organic acids (even CO2), the acidity of which results in A1 migration in the interlayer, but the complexing ability of which is not sufficient for AI removal.
67 citations
TL;DR: The dominant mineral in the clay fractions from the basal horizons of a podzol developed on till derived mainly from chlorite-schists in Argyllshire is oxidized, iron-rich chlorite as discussed by the authors.
48 citations
TL;DR: The role of iron impurities in the analyses of the spectra is also discussed, and a search scheme for Mossbauer investigations of clay minerals is given in this article, where it is shown that iron occupies the octahedral positions and in rare cases also the tetrahedral position.
Abstract: Mossbauer spectroscopy has been used to study iron in clay and related minerals at room temperature. The investigated minerals are kaolinite, montmorillonite, beidellite, bentonite, muscovite, illite, vermiculite, hectorite, biotite and chlorite and, in all, 19 different minerals have been studied. It is shown that iron occupies the octahedral positions and in rare cases also the tetrahedral position. The Fe3+/Fe2+ ratios are determined and compared with the results of chemical analyses. The role of iron impurities in the analyses of the spectra is also discussed, and a search scheme for Mossbauer investigations of clay minerals is given.
34 citations
TL;DR: Montmorillonite, vermiculite, and a sulfonic resin were treated with different concentrations of Al(OH)BCl₃₋B with the basicity B ranging from 0 to 2.2 as mentioned in this paper.
Abstract: Montmorillonite, vermiculite, and a sulfonic resin were treated with different concentrations of Al(OH)BCl₃₋B with the basicity B ranging from 0 to 2.2. The Al exchanged by vermiculite and the resin was always the nonbasic Al³⁺, independent of B and the amounts of Al(OH)BCl₃₋B added. The Al exchanged by montmorillonite was Al³⁺ when exchanged from Al(OH)BCa₀.₅B-montmorillonite containing 32 mmoles Al/100 meq CEC and became basic when large amounts of Al(OH)BCl₃₋B had been added before the exchange reaction. In contrast to vermiculite and the resin, the montmorillonite adsorbed preferentially relatively large OH-Al polymers and, therefore, accumulated much more Al in the interlayers than vermiculite and resin which excluded large OH-Al polymers because of their smaller d spacings and/or high charge densities. When more OH-Al accumulated in the interlayers of montmorillonite, the Al was adsorbed less strongly, and relatively large amounts of basic Al became exchangeable. It was shown also that an Al³⁺-saturated vermiculite is much more unstable than an Al³⁺-montmorillonite. These results are employed to discuss the widely-observed formation of gibbsite when smectite reacts with basic Al. Finally, the exchange acidity from an Al-saturated exchanger was shown to consist of both Al³⁺ and H⁺. The protons come from (i) the hydrolysis of exchanged Al³⁺ which, in turn, can be readsorbed as OH-Al; (ii) from the hydrolysis of adsorbed Al; and (iii) by the exchange of H⁺ from permanent charges. The latter portion mechanism provides an amount of exchangeable acidity that, if it exists, is relatively small.
18 citations
TL;DR: In this article, the authors studied the Roi Et soil, which is a silt loam with low clay contents in the surface horizon; the clay content increases with depth, and found that about a fifth of the clay fraction is soil chlorite -a strongly Al-interlayered vermiculite in the upper horizons but partially Al-Interlayered in the substratum.
Abstract: The Roi Et soil, which occurs on the extensive seasonally wet low terrace, is a silt loam with low clay contents in the surface horizon; the clay content increases with depth. The soil is seasonally water-saturated and seasonally dry, has considerable porosity, but has a dense ploughpan at a depth of about 0.2 m and a dense substratum below 1.4 m. The soil is strongly acid with a low base saturation and a very low cation exchange capacity. The silt and sand are 98% quartz. Disordered kaolinite is the main clay mineral. About a fifth of the clay fraction is soil chlorite - a strongly Al-interlayered vermiculite in the upper horizons but partially Al-interlayered in the substratum. The interlayers contain a small amount of ferrous iron. The quartz contents in the clay fractions range from one tenth in most of the profile to about three tenths in the surface horizon, with a corresponding decrease in kaolinite. The kaolinite in the upper horizons shows signs of dissolution. These data are in accordance with hypothetical clay eluviation-illuviation and long-continued Fe redistribution and ferrolysis, the ferrolysis involving clay alteration and dissolution under conditions of alternating reduction and oxidation of Fe. (Abstract retrieved from CAB Abstracts by CABI’s permission)
16 citations
Patent•
13 Jul 1977
TL;DR: The grain sizes of cellulose and kieselguhr can be varied from 0.4 to 650 microns, and the bulk density of the cellulose is less than 0.40 g/cc as mentioned in this paper.
Abstract: Flame resistant foam plastics of cellulose and kieselguhr or one of several types of mica such as roscoelite, lepidolite, biotite, phlogopite, vermiculite or muscovite where at least 80 percent by weight of the kieselguhr or the mica show grain sizes ranging from 0.4 to 650 microns and where the bulk density of the kieselguhr is less than 0.40 g./cc. and the bulk density of the mica is less than 0.37 g./cc.
13 citations
TL;DR: In this paper, physical, chemical and mineralogical properties of five albic and six spodic horizons were studied in an attempt to relate their composition to their charge properties.
Abstract: Some physical, chemical and mineralogical properties of five albic and six spodic horizons were studied in an attempt to relate their composition to their charge properties. The samples investigated contained less than 3% clay and had specific surface areas less than 30 m2/g. pH values measured in M NaF were lower than 9.5 for the A2 horizons but higher than 10.5 for all the Bir horizons studied. Mineralogy of the clay fraction was studied by using X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis along with selective chemical dissolution analyses. Chloritized vermiculite was the dominant phyllosilicate in the Bir samples, while montmorillonite dominated in the clay fraction of most of the A2 samples. Amorphous constituents, as determined by acid ammonium oxalate and 0.5 N NaOH extractions, represented up to 40% of the clay-sized fraction of some of the samples. Primary minerals such as quartz, feldspars and to a lesser extent hornblende and magnetite were the major constituents of ...
8 citations
TL;DR: The correlation between the content of the clay minerals, mica, montmorillonite or vermiculite, and the logarithmic form pK- 1 2 p (Ca + Mg) of the activity ratio was highly significant for 23 soils from northern Greece.
6 citations
Journal Article•
6 citations
TL;DR: The mineralogical composition of a soil catena from Karroo argillite (shale) from Bengamisa, in oriental Zaire is reported in relation to the particle size distribution and to the extent of quartz enrichment as a measure of weathering.
TL;DR: In this article, the preparation of ammonium-treated vermiculite containing almost 1.3 % ammonium N is described, and the product is relatively stable on storage in air for 3 years, but during leaching with water for 20 weeks, 2.8-4.0 mm flakes released 30% of their N and 0.25-0.5 mm flakes 90%.
Abstract: The preparation of ammonium-treated vermiculite containing almost 1.3 % ammonium-N is described. The product is relatively stable on storage in air for 3 years, but during leaching with water for 20 weeks, 2.8–4.0 mm flakes released 30% of their N and 0.25–0.5 mm flakes 90%. Its potential as a controlled-release nitrogen fertiliser is briefly discussed.
TL;DR: In this article, a commercial sample of vermiculite (1-2 mm grade) in its natural (non-exfoliated) state with ammonia gas gave a product which nitrified more slowly than ammonium sulphate.
Abstract: Treatment of a commercial sample of vermiculite (1–2 mm grade) in its natural (non-exfoliated) state with ammonia gas gave a product which nitrified more slowly than ammonium sulphate. The product has potential as a slow-acting fertilizer although its maximum nitrogen content is only 5–6 per cent. The product formed from exfoliated vermiculite and ammonia gas should be useful as a medium for plant growth because it combines good physical properties with a high rate of nitrogen release. re]19760730
TL;DR: In this article, homoionic forms of montmorillonites and a vermiculite were prepared and their charge characteristics examined by means of differential thermal micro-analysis (DTMA), X-ray and infrared techniques.